Subtyping the behavioural effects of deceit and the implications for detecting deception

Abstract

Identification of deception is crucial in legal, healthcare, social service, and airport security settings because it could be used to facilitate criminal or other harmful activity. However, people generally appear to be poor lie detectors, resulting in additionally serious consequences concerning false accusations of deceit. When judging truthfulness, observers may be limited to considering little more than the demeanour of individuals under question, but research indicates that most behaviours believed to be suggestive of lying have weak or no empirical relationships with deception. Nonetheless, it has been hypothesized that individuals do display signs of deceit, but that different individuals may exhibit different signs. This possibility might result in no signs emerging when analyses are focused on group differences, which is typical of deception research. Despite these propositions, there have been no attempts at subtyping the behavioural effects of deceit. The objective of this research was to determine whether people could be grouped in meaningful ways with regard to similar verbal and nonverbal behaviour changes when comparing lying to baseline truth-telling. Study 1 involved an extended analysis of behavioural cues to deception measured in a sample of undergraduate students (n = 38) and incarcerated offenders (n = 26) who provided both truthful and fabricated accounts of negative life events. Study 2 involved analysis of cues measured in another sample of undergraduates (n = 64) who provided truthful and deceptive accounts of exposure to the same moderately distressing images to better control the events that formed the basis of the accounts. “Fluid” and “laboured” liars were identified in both experiments when difference scores for cues were ipsatized and submitted to cluster analysis, reflecting distinctive changes in speech-related disturbances. Further, offenders in Study 1 were significantly more likely to be classified as fluid liars compared to students, and laboured liars in Study 2 held significantly more stereotypical beliefs about deception cues than fluid liars. Psychological factors that may underlie subtype expression are considered, such as attempted behavioural control and cognitive load. Implications for theory, research, and practice are discussed, including the potential usefulness of a profile-matching approach for detecting deceit.